Cathode ray tube count indicator



June 24, 1958 v. P. MAGNusoN rs1-AL 2,840,311

CATHODE RAY TUBE COUNT INDICATOR 2 Sheets-Sheet 1 Filed Sept. 8. 1952 INVENTOR.

June 24, 1958 v. P. MAGNusoN ETAL 2,840,311

CATHODE TUBE COUNT INDICATOR 2 Sheebs-Sheetl 2 Filed Sept. 8. 1952 CATHODE RAY TUBE COUNT INDICATOR Vernon P. Magnuson, Gardena, and Glenn E. Hagen, Manhattan Beach, Calif., assignors to Northrop Ain craft, Incorporated, Hawthorne, Calif., a corporation of California Application September 8, 1952, Serial No. 308,358 s claims. (cl. zas-92) This invention relates to a system for counting a plurality of signals and for instantaneously indicating the count and more particularly to a system for converting a digital count into an instantaneously intelligible indication on the `face of a cathode ray tube.

ln many computers, it is desired'to make .a count of a variable quantity represented by a pluralityof finite pulses and to provide `an indication of the count. Systems are known for accurately Icounting the' pulses even when the pulses occur very rapidly and build up to a relatively large number. But the circuitry required to produce such a Ifast and high count is relatively `detailed and the number of components, including vacuum tubes, is relatively large.

This invention provides a system which employs a -minimum number of components to produce a large count and an accurate and instantaneous indication of 'thecount The system minimizes the number of components by ernploying a relatively few multivibrators to count a predetermined number and by reinstituting the count inthe multivibrators every ltime that the predetermined number or a multiple thereof is counted.

The system also employs a cathode ray tube havingits face masked to provide a plurality of rows rising diagonally. Every time that an integral multiple of the predetermined number is counted, the beam in the tube completes its movement through one row and commences its movement in the row immediately above the r'st row. By noting the number of rows traversed by the beam and the exact position of the beam in the 'r-ow, lthe total number counted can be easily determined.

An object of this invention is to'provide `a system for producing an instantaneous and reliable indication of a atejnt relatively high pulse count on the lface of a cathode ray tube.

Another object is to provide a system of the above character yfor converting a digital count of pulses into an analogue indication represented by the position of a beam on the face 'of a cathode ray tube.

A further object is to provide a system of the above character requiring a minimum number of components to produce a fast and reliable indication of a relatively large count of pulses.

Still another object is to provide a system of the above character which can count pulses at a faster rate than systems now in use because of the elimination of all movable parts such as relays.

A still further object is to provide a system of the above character which is simple, compact and accurate.

AOther objects and advantages will be apparent froma `detailed description of the invention and from the appended drawings and claims.

In the drawings:

Figure l is a circuit diagram, partly in block` form, of one embodiment of the invention;

Figure'Z is an enlarged view illustrating in detail the appearance of the face of a cathode r-ay tube shown in Figure 1 and Patented `June 2,4, s

Z t Figure 3 is a chart illustrating the pattern in which cer'- tain of the components shown in Figure l operate. l

In one embodiment of the invention, a source 10 is adapted to provide clock pulses at regular intervals.Y The pulses from then source 10 Yare introduced through a crystal diode 12 to the grid of the left tube in a flip-op multivibrator 14 and through a crystal diode 16 tothe grid of the right tube in the multivibrator. In like` manner, the signals from the source 10 are'introduced to a4 crystal diode 18 associated with the grid of the left vtube in a ilip-llop multivibrator 20 and to a `crystal diode ,'22 associated with the grid of the Vright tube in the multivibrator. A K f Connections are also made to the grid ofthe left tube in the multivibrator 14 through acryrstal diode 24 lfrom the plate of the right tube in the multivibrator 'and through a resistance 26 from the positive terminal of a suitable Ypower' supply, such as a battery 28. Similarly, the grid of the right tube in the multivibrator is connected through a crystal diode 30 to the plate of the left tube in the multivibrator and through a resistance 32 to the positive terminal of the battery 28. u Y

-In addition to being connected to the diode 30, the plate Vof the left tube in the multivibrator -14 is connected Yto crystal diodes 34 and 36 associated with Vthe grids ofthe left and right tubes, respectively, in the multivibrator 20. In like manner, the plate of the right tube in the multivibrator 14 is connected to crystal` diodes 38 and 40 associated withV the multivibrator 20. Connections. are madey from the plate of the left tube in the multivibrator 20 Ato crystal diodes 42 and 44 and from the plate of the fright tubesin the multivibrator rto crystal diodes 46 and 48;

Crystal diodes so, sz, s4 andes -are'connected to a source S8, which produces pulses at substantiallyfthe same instant that clocking signals are produced by the Ysource 10. The diodes 50 and 52 receive positivesignals from one'terminal ofthe source 58, and the diodes 54 and 56 receive positive signals from another terminal of the source. The pattern'of thepositive and negative signals from the source 58 may correspond to the signals obtained from'a pickeup head upon the rotation of a'magnetic drum contiguous to the pick-up head. Positive and negative signals are obtained from the pick-up head in accordance with the pattern of magnetic pulses provided on the periphery of the drum.' The use of a magnetic drum and pick-up head-to obtain positive and-negative signals is fully disclosed in copending application Serial No. 217,478, tiled March 26, 1951 by Floyd'G. Steele and William F. Collison. v f j The plates of the diodes 38, 46 and Si) are connected through a resistance 60 to the positive terminal of the battery 28 andare directly connected to the plate of `a diode 62. Similarly, connections are made from the platesofthe dodes 34, 48 Vand 54 through a resistance 64 to the positive Vterminal of the battery 28 and directly to the plate of a diode 66. LThe cathodes of thediodes 62 and 66 are connected to a grounded resistance 68 and to the cathode of a diode 70. Connections areimade from the plate'of the diode 70 vto the plate of the diode 18,

` to the grid 'of the left tube in the multivibrator 20 andi-to Amanner similar tothat disclosedabove. The cathodes of the diodes are connected to a grounded resistance l78 Vand to the cathode of a diode 8i). The plates of the diodes `22 and'80 are in turn connected to the grid of the right Ytube inthe multivibrator 20 and toa resistance 81 in series with the battery 28. Y p

In addition to the flip-op multivibrators 14 and-,20,l a

astantik i Ving its negative terminal grounded,

pair of flip-Hop multivibrators 82 and 84 are provided. The grid of the left tube in the multivibrator 82 is connected to a diode network shown in block form as a gate circuit86, and the grid of the right tube is connected to a diode network shown in block form as a gate 88. Connections are also made from gate circuits 90 and 92 to the grids of the left and right tubes, respectively, of the multivibrator 84.

The use of multivibrators, as the multivibrators 14, 20, 82, and 84, for counters by intercoupling in a manner similar to that shown between the multivibrators 14 and is well known 'in the art. One such arrangement is shown in Figure 33 of co-pending application Serial No. 217,478 tiled on March 26, 1951 by Floyd G. Steele and William F. Collison. The equations disclosing the logic behind the particular connections of the different diodes forming each gate are shown in Figure 29 of the co-pending application. An arrangement is also shown for setting up four multivibrators, as the multivibrators 14, 20, 82, and 84, to accumulate a pulse count in an article entitled The binary quantizer by Kay Howard Barney, beginning on page 962 of a magazine Electrical Engineering, for November 1949.

The plates ofthe right tubes in the multivibrators 14, 20 and 82 are connected to resistances 94, 96 and 98, respectively. The resistances 94, 96 and 98-have a common terminal which is connected to a resistance 100 in series with a battery 101 having its positive terminal grounded. The resistances 94, 96 and 98 havepredetermined values relative to each other. For example, if the resistance 94 has a value of approximately 4R, the resistances 96 and 98 may have values of approximately 2R and R respectively; Y

T he common terminal between the resistances 94Y and 100 is connected to a plate 102 for deilecting the` beam in a cathode ray tube 104 in a horizontal direction. A second plate 106 for controlling the horizontal deiiection of the beam in the tube 104 is grounded. The face of the tube 104 has opaque portions which define a plurality of transparent strips 108 (Figure 2). The bottom of each transparent strip is defined by a plurality of notches which riseV diagonally, and the top of each strip is defined by a plurality of similar notches. In this way, each strip defines a pair of notched rows 110 and 112 (Figure 2). The top notch of each row is slightly below the bottom notch of the next highest row. An appropriate numeral `may be printed adjacent each notch and on the transparent portion of the tube face to provide an instantaneous indication of the pulse count, as illustrated in Figure 2.

, A photo tube 114 having a plate and a cathodeis positioned in front of the face of the cathode ray/tube 104 to provide a current when the beam in the cathode ray tube is incident on one of the transparent strips 108. The tube 114 .is so disposed that it is sensitive only toflight from the cathode ray tube 104. The anode of the tube 114 is connected to the positive terminal of the battery 28, and the cathode is connected to a grounded resistance 116 and to an input terminal of van amplifier 118 shown in block form. The output terminal of the amplifier 118 is connected to the grid of a tube 120 and to the input terminal of an ampliiier 122 also shown in block form. The output terminal of the amplier 122 is in turn connected to the grid of a tube 124. v

Voltage is applied to the plate of the tube 120 through a suitable' resistance 126 from the positive terminal'of the battery 28. The cathode of the tube 120 is connected to the cathode of a tube 128 and to one terminal of a resistance 130, the other terminal of which is connected to the positive terminal of a bias battery 132 hav- Connections are made from the plate of the tube 128 to the positive terminal of the battery 28 and from the grid of the tube 128 to the plate of the right tube in the flip-Hop multivibrator 84.

Similarly, a positive voltage is applied from the positive terminal of the battery 28 through a suitable resistance 134 to the plate of the tube 124. The cathode of the tube 124 is connected to the cathode of a tube 136 and to one terminal of a resistance 138 having its other terminal connected to the positive terminal of the battery 132. The plate of the tube 136 has a positive voltage applied to it from the positive terminal of the battery 28, and the grid of the tube 136 has a voltage applied to it from the plate of the left tube in the multivibrator 84.

in addition to being connected to the resistances 126 and 134, the plates of the tubes and 124 are respectively connected to the control grid and the suppressor grid of a pentode 140. A slightly positive bias is applied to the cathode of the pentode 140 through a resistance 142 in series with the battery 132. A positive voltage is applied to the screen grid of the pentode 140 from the battery 28, and a positive voltage of relatively large magnitude is applied to the plate of the pentode through a resistance 144 from a battery 146 in series with the batteries 28 and 132. The voltage on the plate of the pentode 140 is in turn applied to a plate 148 for producing a vertical deflection of the beam in the cathode ray tube 104. A second plate for controlling the vertical deection of the beam is connected to the battery 28.

The multivibrators 14, 20,. 82 and 84 are connected in an arrangement to provide a digital count on a binary basis of numbers 'from 0 to 15. For a count of 0, the left tube in each multivibrator is cut oft,V and the right tube is conducting because of a relatively high voltage on the grid of the tube. Since the right tubes in the multivibrators are conducting, the voltages on the plates of the right tubes are relatively low. This is indicated in Figure `3 by a numeral 0 in the column for each multivibrator.

When a iirst positive signal is introduced from the source 10 to the cathode of the diode 16, the positive voltage on the cathode of therdiode relative to the voltage on the plate prevents current from flowing through the diode. Current also is unable to flow through the diode 30 since a positive voltage is applied on the cathode of the diode from the plate of the left tube in the mu1tivibrator because of the non-conductivity of the left tube. Since current is unable to ow through either the diodes 16 or 30, the voltage on the grid of the right tube in the multivibrator 14 remains high.

At the end of the pulse from the source 10, the voltage on the cathode of the diode 16 becomes relatively low and causes a current to flow through a circuit including the battery 28, the resistance 32 and the diode 16. This current produces a voltage drop across the resistance 32 and causes the voltage on the grid of the right tube in the multivibrator 14 to drop below the value produced during the absence of any current through the resistance. The voltage drop on the grid of the right tube of the multivibrator 14 causes the tube to become cut off and a relatively high voltage to be produced on the plate of the tube. Figure 3 by the numeral "1 in the column for the multivibrator 14. Such a designation indicates a numerical'count of 1.

When a relatively high voltage is produced on the plate of the right tube in the multivibrator 14, it is introduced to the grid of the left tube in the multivibrator to produce a conduction of the tube. Upon the production of the next positive pulse by the source 10, the coincidence of this pulse with a relatively high voltage on the cathode of the diode 24 causes the left tube in the multivibrator 14 to become cut off and the right tube to start conducting. In this way, each of the two tubes in the multivibrator 14 is triggered into a state of nonconductivity upon the introduction of alternate signals from the source 10.

As indicated by the chart in Figure 3, the right tube in the multivibrator 20 is changed from a state of con- This relatively high voltage is designated in ductivity to state of- Irion-conductivity? when 'the plate j of the'right tube in the multivibrator 14 and.V 'theplate of Y the leftitubein the multivibrator 2l)y have relativelyhigh voltages applied tovthem,y Iii addition yto'^th`ese 'voltage states, a positive pulse Lof. voltageJmu'stFbe applied toV the Vdiode 52 from the source 58 beforeranycurrent flow through the resistance 76 Vcan' Abe interrupted fUpon` Vthe, simultaneous occurrence of Ythese voltage states, a

positive signal appearson the plate of the diode 74 and causes f currentA to Vilow` through 'a circuit including the battery 28', 'the resistance 76, the diode 7e and the resis'tance'78.

The positive voltage produced lacross theresistance 78 by the How of current through nthe resistance causes the voltage lon the;ca thode of the diode-80 to rise.Vv At the sametime, the voltagev'non the cathode of-the diode22 n'ses because f the introduction vof a clock pulse from the source 10. When these voltagerelationshipsoccur,

`fthe. voltage, on the 'grid ofthe right tube infthe'multivi- Ibrator-20 remains high because of the interruption Aof'auy current 'flow througlrthe resistance 81,' VThev voltage on the gridl of the multivibrator tube remains relatively high until'the endof the `pulse from the source 10: At the :end of this pulse, current owsthrou'gh the 'resistance 81 and rthejdiode" 22 and causes the "voltage Yon theig'rid of.

like manner, 'the relativelyfhigh volta'geon the' plate -fofl'theiri'ght 'tube in the multivibrator 20 when the'tube lisi citoll'auses anincreased current to flow through-'the resistances 96;and100. Since the` resistance 96` hasa *smaller-value'than the resistance 9`4,thev current throughv the resistance 1001is `greater thanthellcurrent when the right Vtube lin the multivibratorl14 is cutoff. This causes the voltage. at the common terminalbetween the resist- .ances a96a`ndl100-to increase over thatproduced by cutting offithefright tube in the multivibrator 114.

. (The voltage at thecommon terminal between the rei sistance 96 and100 'rises still further when therightltube i .in the multivibrator 82ispcutzotf, since .the resistancel98 -ha'sa lower resistance .than Y.either .the resistancesV 94'lor V96, By cutting oldierent combinations .of the right tubes in the mnltiyibrators .14,'20fan'd 82,. the-voltageat the )common terminal'bletween the resistances96 and'lQl) Y 4can be -progressivelyincreased. In this. Way,;.the.voltage the rightftube inltheY multivibrator Y to Vfa'litfjfIhis `f all in voltage causes the right multivibrator vtubeto be triggered into a conditionof non-conductivity. A.Zlswindi- .cated by the numeralnthe Column. for the multivibrator .20, a positive ',.vQltge on ,thefpilate 0f 'the 4right tube in the multivibrator v20" i n d ic` tesfaf count .0.f"2.'

in lilce manner, the left tube in .themultivibrator 2 0 istriggered into a state of nollrllfdctivity upon the simultaneousfintroductin o f positivef.voltagest tofthe the plates of the'iight tubes in'the multivib'rators1 and 20 are relativelyhigh and positive voltage pulses yare sirnultaneously `introduced 1 from the sources 1 10 :and Q58."

When the source 58 .fails to. produce Va positive signal atsubstantiallythe same instant as the production ot a vc loclgpulse bythe source 10, an indication is provided that an integer must be-subtractedfromthecount previously made. For exan1ple, if the count is @-4, at .such a time, an integer must be subtracted from the value of |4 to indicate a resultant value of +3. t flheindicatiouto .subtract an integer is provided jby a positive pulse from the left terminal of the source 58. I t u The positive pulse fro1 r 1 the left lterminal in vthesource 58 is applied to diode networkswassociated with the left and right tubes-inthe multivibrator v20,. Upon, the `in-V troduced to the diodes 18, 34 and 48.y Similarly, the

right tube in the multivibrator 20' becomes ,eut ol when a pulse is introducedto the ;liode 56 from the left terminal in the source S8 at the same timje that relatively high voltages are applied to the diodes 22, 36' and 44.

The count` of the positive and negative signals fromthe source 58 continues into the multivibrators 82-`and84 in a similar manner in accordance Awiththe passage of signals through the gates 86, 88, v901and 92. The .passage of signals through each gate-is determined levels on the diodes forming the gate. y v

During thetime that the right tube in the multivibrator 14 is cut ol, vthe relatively high voltage on the plateot the tube causes'a large current to V:flow through the resistances 94 and 100;f1`he increased ilow of current' through therersistanceV 100 produces a rise in the voltage at the common terminalbetweenthe resistan'ces 94. and

y vtitluover voltage prcduce'ctat terminal .when the v oltageon theplateof the right tube isv relatively low.

, .as diodes 18, 38, V46 andAISl). Such laV simultaneou's'v-introf duction of positive voltages occurs when thevoltagesionu at vthe common terminalzbetween itheresistancesd and Lliiprovides an indication of th'epulse'count'in the multieicommonierminal between/the' re- .eathodevfray'tubenm. .The distancefth'r'fmghy which Vthe :beamiisgdeectedincreases with'increments `in the count @provided by themultivibrators 14,'20 and 82V.` Uponfa .countof.7,.,thebeam ,is deflected horizontally through .f amaximum distance beCausethe righttubes in all lofthev multivibrators 14, 20 .and 8 2;are c'ut .olifl When thecount isf-,increasedby aninteger vto the nu- Y n reral. 8, theY rightitubes -in the multivibrators r14, Ztl

andLlgv again become conductive, and the beamis returned to its original position at the left of =the tube 124. This fprocessgisvrepeated upon az transition from av count. :of

count off1`6 landlgupon, every; subsequent in- Y 87; ora multiple thereof.

Upon-aufincreas'ein count in therange from O to 7,fr -th`e beam is .deilectedhorizontallyto the right, as

Ydiselosedabove This causes lthe beamto move horivgontallyfrom aftransparent portion vto an opaque portionofthe tube 104.v When thebeamis in the opaque portion Lof the tube `10kt, no current ows through the 'ttubelf1v14 or theresistancef116. The resultant low volt- Viagetproducedracrossthe resistance 116 is amplified and inverted by thejamplier 118 and introduced in positive form j to thegridof the tube 120. Sincetheftube 1Z0 has a cathode resistance 130 commonto it and thevtube 128,- the-state'ofrconductivity of the tube 128` affects the by the voltage 128 -.beemes cut,ol, thevoltageon the cathode ofthe 'tubegllsebeause.Othefailure of anycurrenttolow Y thrugh the resistance 1.3.0-19- The^comb ination of therelatively'low, voltage ont. the cathode ofthe-tube 12 0 and the relatively highvoltage- -onjthe gridof the tube causes the tube to startcouduct` ing and a relativelylowl voltage to be produced-on ."thexfl il plateot Ythe tube.I Thisvoltage' is introduced tothe grid of the/pentode'140`to'utfolthe tube. Upon the: cut- ;ot of ,thegpentode'140,- current flow through the resistance y `Whenjthe beam reaches the transparent; portion 108,

current Yllows throughthe Ytube v1414A and produces a .pos-

itive .voltage vacross the resistance 1116. yAfter being "am` pliiied and inverted, the positive voltage across the resistance .116 is introducedto the grid of the tube. 120 as a relatively low voltage. This voltage. is sufliciently low to cause the tube 120'to'become cut olf even though the voltage on the cathode of the tube is relatively low. The

resultant high voltage onthe plate of the tube'120 is in-V troduced to the control grid of the pentode ,140f Y.

The relatively high voltage produced across the 'resistance 116 is also introduced tothe grid of the tube 124. The tube `12'4`is associated with the tube 136 as a result ofthe commonresistance 138. Since the tube 136 has a relatively high voltage introduced to its grid from the plate of the left tube in the multivibrator, current iiows through it. and the resistance'138 and produces a positive voltage on its cathode. itive to cut off the tube 124 even though' a positive voltage is introduced to the'grid of the tube. Y The resultant positive voltage on the plate of the Ftube 124 is applied to the suppressor grid of the pentode 140. l

Because of VtheV positive voltages; on the control Vand suppressor grids of the pentode 140, Vcurrent flows through the resistance 144'and the pentode and causesa relatively iow voltage to be produced on the plate of theV pentode. When introduced tothe plateV 148, this voltage produces -a downward deflection of the'beam inthe tube 104 into the opaque portion of thev tube. 'Upon the movementY of the beam into the Vopaque'portion of thejtube 104, the pentode 140 again becomes cut olf and introduces'a relatively high voltage to the plate 148 to produce an upward movementof the beam. Y ,t

In this way, the beam oscillates vertically at a horizontal position indicative of the Vpulse count. The oscillation occurs at such a rate as to provide an indication ofthe beam position on the transparent portion of Vthe tube 104. Because of thenumeral printed on the trans# parent portion of the tube 104` adjacent'each notch, an

instantaneous indication -is provided `of the pulse count.Vv

During a count from8Y to 15,V then'ght tube in the multivibrator 84 is cut ol and alrelatively high voltage is produced on the plate of the tube for introduction to the grid of the tube 128. This .voltage causes the tube v128 to conduct( and the voltage on the cathode of the .tube to become relatively high. Because of the common connection between the cathodes ofthe tubes 120 and 128, theV relatively high voltager onV the cathode of Vthe tube 120 prevents the tube from Aconducting regardless of whether a high or low voltage i s introduced to its gridfrom the amplifier 11S. i j Y Since the left tube in the multivibrator `84 is conducting at the time that the right tube i's cut on, Va relatively low voltage is produced Von the plate of the left multivibrator tube and is Vintroduced to the grid of the tube'136. This voltage prevents the tube 136 from conducting so that fa relatively low voltage is produced at the common terrninal between the cathodes' ofthe tubes 136 and 124. Because of the relatively low voltage on the cathode of the tube' 124, the tubefeonductswhen a relatively high signal is introduced to its'grid and becomes cut olf when a relatively low signal is introduced to its grid. 1

A relatively high signal is introduced to the grid of the tube V1214 when the beam in the cathode ray tube 104 'is incident upon a transparent strip 108. VThe relatively Ilowfvoltage produced at the'plate of the tube 124 as a resultV of the current flowing through the tubercauses the -pentode 140 to become cut oi and a relatively high :voltage to be .introduced fromthe plate of the pentode .to the deecting plate 148. This high voltage actsto .produc'ean upward movement of thebeam from the V.transparent region adjacent the bottom row 1812 tothe .opaque region immediately abovev the row. Y

When the beam becomes incident upon the 'opaque' portion ofthe tube, aV signal havingV a relatively low voltage isprodu'ced 'atthe output terminal of the amplifier 122-21m is introduced te the 'gn'd 'of the v'tube 1245.9

This voltage is suciently 1`Jos-A as vto V"cut off` the tube. .'.I'heresultant high` voltage `on VVthesuppressor grid v,of Vthe pentode 1 40.in"combination with the high voltage on thef control grid of thepentode i causes a current to ow through the pentode and a relatively low voltageto be applied on the plate 148. The

I --relatively lowvoltage on the plate 148 produces a down- 'gward movementjfof the beam. In this way, the beam tionltoV the transparent portion ofthe tube104 when the countis between 0 and 7 and to'move `downwardly into the. transparent Vportion when the count is between Y t8 and "u15. This corresponds to the opposite disposi- Vtions o f the rows '110 andj112rrelative to theopaque Y portion of the tube.

I n like manner, theAfmultivibrator 84 acts to4 control the movement of the beam in the proper vertical direction for, counts above the numeral f15. Vertical control of the beam is maintained even while the beam moving from the right Aend of one row tothe left end of the next highest row. Such vertical control is maintained because the beam. is moving Aentirely within the transparent por-- tion Vof the tube upon the continuance of a count from a row 110 toa row 112 and it fis moving entirely within ,i the opaqueV portion of the tube upon the lcontinuance i any movable parts such as relays.

iover' the widenrange.

of a countV from a row 112 to a row 110.

. The systemvdisclosed above has several important advantages. It provides an instantaneous visual indication of the count that has been made of pulses from a source and it is capableof providing such an instantaneous indication over a 4 relatively wide numerical range, While lat the same time it provides an analog voltage representa- Ativre'of the-digital value indicated and registered. The analogy voltage vbeing the voltage appearing at the plate 148 of lthe tube 104,01- at the plate of the tube 140. The system'is also advantageousinthat it requires a minimum ,numbenof counting` stages; such. as the multivibrators be easily adapted to provide'indications of negative counts as well. This can be accomplished by providing on the face of the tube. 104 transparent strips which move diagonally downward with progressive increases in distance from left to right.l Suchstrips have not been shown for purposes of simplification and convenience.

Although this invention hasgbeen disclosed and illustrated with reference to particular applications, the principles involved are susceptible of numerous other applica- Vtions which will be apparent to persons skilled in the The invention is, therefore, to be limited only as indicated by the scope of the appendedclaims.

What is claimedis: 1 A

1. In combination, a cathode ray tube, means for deecting a beam in the tube in a iirst direction, means for deilectingV the beamfin a second Ydirection substantially perpendicular tofthe first direction, means for providing on the face of the tube opaque portions of diagonal configuration with respect to said first and said second4 directions, the opaque portions being disposed ;to provide a plurality of similarly diagonalparallellight-transmissive strips, means forproviding a digital count of a finite quantity, means for providing increased. displacements of the beam in the rst direction with inc-reassin the digital count, means for returning the beam to its initial position in the first direction upon each full displacement of the beam in that direction,'an d means for displacing the beam in the second Adirection'` through a ldistance dependent 'UPI thztotalinovement of the beam in the rst direction.

the digital count, means for returning the beam to its f original position in the irst direction upon each full displacement of the beam in the rst direction, means for displacing the beam in the second direction in accordance with the displacement of the beam in the first direction and through a distance to maintain the beam in a light-transmissive strip of the tube, and means for alternating the direction of movement of the beam in the second direction to maintain it within a light-transmissive strip of the tube upon each return of the beam to its original position in the rst direction.

3. In combination, a cathode ray tube, a first pair yof plates in the tube for displacing a beam in the tube in a horizontal direction, a second pair of plates in the tube for displacing the beam in a vertical direction, means for masking the face of the tube to provide a plurality of transparent areas extending diagonally upwardly on the face of the tube, a counter for providing a digital count of a finite quantity, means connected between the counter and the first pair of plates in the cathode ray tube for displacing the beam progressively in the horizontal direction upon each increase in the digital indications of the finite quantity, means for returning the beam to its initial position in the horizontal direction upon each integral multiple of a predetermined number in the digital count, and means connected to the second pair of plates Y in the cathode ray tube for displacing the beam in they vertical direction in accordance with the progressive displacement of the beam in the horizontal direction to maintaining the beam within the transparent rows on the face of the tube for providing a visual indication of the digital count, and an analog signal indication of the digital count.

References Cited in the file of this patent UNTTED STATES PATENTS 2,404,106 Snyder July 16, 1946 2,462,263 Haynes Feb. 22, 1949 2,513,442 Baker July 4, 1950 2,540,016 y Sunstein Jan. 30, 1951 2,568,449 Hansen Sept. 18, 1951 2,591,842 Llewellyn Apr. 8, 1952 2,603,418 Ferguson July 15, 1952 2,715,678 Barney Aug. 16, 1955 OTHER REFERENCES Theory and Techniques for Design of Electronic Digital Computers, volume III, Univ. of Pa., Moore School of E. E., Phila., Pa., June 30, 1948; pages 3-19 to 3-26, 33-11 to 33-13, and 33-18. 33-27 and 33-35, dwgs. 33-36 to 33-38. 

